Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
In many wireless networks (e.g., UMTS), a connection between a user equipment (UE) and the network can transition among different states. In UMTS, a UE can transition from a state where a dedicated channel is assigned to the UE to one or more various standby states or an idle state. When the UE transitions to the state to acquire a dedicated channel, the UE may start a random access procedure by randomly selecting an available signature sequence out of a fixed number of sequences, and may transmit a preamble modulated with the selected signature sequence on a physical random access channel (PRACH). However, the randomly selected signature sequence may not always correspond to an available dedicated channel.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.